diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 6c0e20e8e..fa5948ded 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -233,6 +233,8 @@ set(SRB2_CONFIG_HAVE_OPENMPT ON CACHE BOOL
 	"Enable OpenMPT support.")
 set(SRB2_CONFIG_HAVE_CURL ON CACHE BOOL
 	"Enable curl support, used for downloading files via HTTP.")
+set(SRB2_CONFIG_HAVE_THREADS ON CACHE BOOL
+	"Enable multithreading support.")
 if(${CMAKE_SYSTEM} MATCHES Windows)
 	set(SRB2_CONFIG_HAVE_MIXERX ON CACHE BOOL
 		"Enable SDL Mixer X support.")
@@ -473,6 +475,12 @@ if(${SRB2_CONFIG_HAVE_CURL})
 	endif()
 endif()
 
+if(${SRB2_CONFIG_HAVE_THREADS})
+	set(SRB2_HAVE_THREADS ON)
+	set(SRB2_CORE_HEADERS ${SRB2_CORE_HEADERS} ${CMAKE_CURRENT_SOURCE_DIR}/i_threads.h)
+	add_definitions(-DHAVE_THREADS)
+endif()
+
 if(${SRB2_CONFIG_HWRENDER})
 	add_definitions(-DHWRENDER)
 	set(SRB2_HWRENDER_SOURCES
diff --git a/src/sdl/CMakeLists.txt b/src/sdl/CMakeLists.txt
index 72f78188f..bb5edf817 100644
--- a/src/sdl/CMakeLists.txt
+++ b/src/sdl/CMakeLists.txt
@@ -55,6 +55,10 @@ set(SRB2_SDL2_HEADERS
 	sdlmain.h
 )
 
+if(${SRB2_CONFIG_HAVE_THREADS})
+	set(SRB2_SDL2_SOURCES ${SRB2_SDL2_SOURCES} i_threads.c)
+endif()
+
 source_group("Interface Code" FILES ${SRB2_SDL2_SOURCES} ${SRB2_SDL2_HEADERS})
 
 # Dependency